Book Image

KVM Virtualization Cookbook

By : Konstantin Ivanov
Book Image

KVM Virtualization Cookbook

By: Konstantin Ivanov

Overview of this book

Virtualization technologies such as KVM allow for better control over the available server resources, by deploying multiple virtual instances on the same physical host, or clusters of compute resources. With KVM it is possible to run various workloads in isolation with the hypervisor layer providing better tenant isolation and higher degree of security. This book will provide a deep dive into deploying KVM virtual machines using qemu and libvirt and will demonstrate practical examples on how to run, scale, monitor, migrate and backup such instances. You will also discover real production ready recipes on deploying KVM instances with OpenStack and how to programatically manage the life cycle of KVM virtual machines using Python. You will learn numerous tips and techniques which will help you deploy & plan the KVM infrastructure. Next, you will be introduced to the working of libvirt libraries and the iPython development environment. Finally, you will be able to tune your Linux kernel for high throughput and better performance. By the end of this book, you will gain all the knowledge needed to be an expert in working with the KVM virtualization infrastructure.
Table of Contents (15 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Managing CPU and memory resources in KVM


Changing the amount of allocated memory or the number of CPUs can be done either by editing the XML definition for the VM or using the libvirt toolset. In this recipe, we are going to look at examples of changing both the memory and the CPU count for a KVM instance.

Getting ready

For this recipe, we are going to need the following:

  • A running KVM instance with 1 GB of memory, 1 CPU allocated, and console access
  • The libvirt package
  • A guest OS with at least 4 GB of available memory and minimum of 4 CPUs

How to do it...

To inspect and update the memory and CPU resources assigned to a virtual machine follow the process outlined here:

  1. Get memory statistics for the running instance:
root@kvm:~# virsh dommemstat kvm1
actual 1048576
swap_in 0
rss 333644

root@kvm:~#
  1. Update the available memory for the VM to 2 GB:
root@kvm:~# virsh setmem kvm1 --size 1049000

root@kvm:~#
  1. Stop the running instance:
root@kvm:~# virsh destroy kvm1
Domain kvm1 destroyed

root@kvm:~#
  1. Set the...